#! /usr/bin/python

a = 0
b = 1

def fibonacci(num):
  while c < num:
    if num == 0
     return 0 
    else
     return a
     return b
     c = a + b
     return c
     a = b
     b = c

def main():
  fibonacci(4)
  fibonacci(13)

if __name__ == '__main__':
  main()


